Photographic element and method of identification



March 23, 1954 R. H. TALBOT 2,673,153

PHOTOGRAPHIC ELEMENT AND METHOD OF IDENTIFICATION Filed Oct. 19, 1950 PHOTOGRAPH/C .SIL VER HAL/DE EMULSION ecu ULQYE ESTER CONTAIN/N6 LESS THAN 0-22 ANTHRACENE RALPH H TALBOT l iii/\VENTOR MZK 7/ ATTORNEY Z9 AGENT Patented Mar. 23, 1954 r. 2,673,153

UNITED STATES PATENT OFFICE,

PHOTOGRAPHIC ELEMENT AND METHOD F IDENTIFICATION Ralph H. Talbot, Rochester, N. Y., assignor to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey Application October 19, 1950, Serial No. 191,017 Claims. (01. 959) This invention relates to photographic elethat over a certain range anthracene could be ments and a method for identifying them. advantageously used without having a deleterious Motion picture film is ordinarily identified aceffect on the photographic emulsion. Anthracording to the manufacture and type (e g cellucene has no detectable efiect on the color of the lose acetate 01 cellulose mtiate) by exposing leti film base and is insoluble in water or the soluteis or symbols photographically along the martions used in film processing, when used in acem 0f the raw or unprocessed film Upon decordance with the process of my invention velopment these markings become visible and Whereas the use of fluorescent materials in permit identification of the fil mks and the like for identifying certain mate- The difliculty with such a means of identificall be distinguished from cellulose nitrate type film. With my invention.

It is, therefore, an object of my invention to The accompanying drawing shows a film base provide a new photographic element. A further of a cellulose ester containing anthracene and ly Sti 1 another ob ect is to provide a new comthe photographic elements of my invention is position of matter. Other objects W111 become g ven owapparent from a consideration of the following The amount of anthracene used in my invention description and examples. is of material importance in determining the containing from 0.01 to 0.20 per cent by weight, ing the cellulose ester film base. An amount based on the cellulose ester, of anthracene. On less than 0.01 per cent should not be used, nor

vention are not obtained outside this iange. It is known that fluorescent materials can be The anthracene can advantageously be added added to the film base of photographic elements. to a viscous solution or dope of the cellulose For example, Michaehs U. S. Patent 2,311,492, ester, and the composition agitated until homoelement containing a fluorescent material, such be added in solid form, or in the form of a soluthe amount of anthracene used cannot be as systematically controlled and the anthracene is easily removed from the film base during handling.

Cellulose esters which can advantageously be used in my invention comprise cellulose acetate, cellulose propionate, cellulose butyrate, etc., mixed cellulose esters, such as cellulose acetate butyrate, etc., and cellulose nitrate. My invention is particularly adaptable to the use of cellulose acetate containing, for example, from 35 to 44.8 per cent acetyl. The particular solvent, or mixture of solvents, used in the cellulos ester dope will depend on the acyl content of the ester. For example, cellulose acetate containing from about 39 to 41 per cent acetyl can be dissolved in acetone.

Cellulose acetat containing from about 42.5 to 44.0 per cent acetyl has been found to be especially useful in preparing the photographic elements of my invention. A range of acetyl from 43.0 to 43.5 per cent gives particularly useful results. The anthracene can be readily incorporated into such esters by addition to a solution of the ester in a solvent mixture composed of 55 to 85 per cent by weight of methylene chloride, 15 to per cent by weight of methanol or ethanol, and 30 to 5 per cent by weight of ethylene chloride. By replacing the ethylene chloride with propylene chloride, the methylene chloride can comprise from 65 to 90 per cent by weight of the solvent mixture. Cellulose acetate containing from 42.5 to 44.0 per cent by weight, and more particularly from'43.0 to 43.5 per cent by weight, of acetyl provides a film base possessing unusual resistance to tear and separation when subjected to stress or strain. (See, for example, Fordyce et al. U. S. Patents 2,492,977 and 2,492,978, dated January 3, 1950.)

The accompanying drawing illustrates, schematically, a cross ectional view of a photographic element representative of those of my invention. The element comprises a support 19 of a cellulose ester, such as those described above, containing less than 0.20 per cent of anthracene (e. g. 0.02 per cent) having thereon a photographic silver-halide emulsion H. Instead of a single photographic silver-halide emulsion, the support it can be coated with a plurality of emulsions, for example, as shown in U. S. Patents 2,350,764, dated June 6, 1944; 2,360,214, dated October 10, 1944; 2,376,202, dated May 15, 1945; 2,391,198, dated December 18, 1945; 2,403,721, July 9, 1946; etc. The photographic emulsion layer H, and those described in the above U. S. patents are the usual gelatino-silver halide emulsions customarily used in the art of black-and-white or multicolor reproduction. These emulsions can also consist of silver halide dispersed in other waterpermeable colloidal materials, such as synthetic resins, e. g. polyvinyl alcohol, etc., cellulose ethers and esters, etc. Typical silver halide emulsions include silver chloride, bromide, bromiodide, and chlorobromide types. The photographic silver halide emulsions can contain the usual addenda, such a polymethine sensitizing dyes, anti-foggants, etc.

What I claim as my invention and desire secured by Letters Patent of the United States is:

1. A photographic element comprising at least one photographic silver halide emulsion layer and a colorless cellulose acetate layer containing from 0.01 to 0.20 per cent by weight, based on the cellulose acetate, of anthracene, said cellulose acetate containing from 42.5 to 44.0 per cent by weight acetyl.

2. A photographic element comprising at least one photographic silver bromide emulsion layer and a colorless cellulose acetate layer containing from 0.01 to 0.20 per cent by weight, based on the cellulose acetate, of anthracene, said cellulose acetate containing from 42.5 to 44.0 per cent by weight acetyl.

3. A photographic element comprising at least one photographic silver chloride emulsion layer and a colorless cellulose acetate layer containing from 0.01 to 0.20 per cent by weight, based on the cellulose acetate, of'anthracene, said cellulose acetate containing from 42.5 to 44.0 per cent by weight acetyl.

4. A photographic element comprising at least one photographic silver bromiodide emulsion layer and a colorless cellulose acetate layer containing from 0.01 to 0.20 per cent by weight, based on the cellulose acetate, of anthracene, said cellulose acetate containing from 42.5 to 44.0 per cent by Weight acetyl.

5. A photographic element comprising at least one photographic silver chlorobromide emulsion layer and a colorless cellulose acetate layer containing from 0.01 to 0.20 per cent by weight, based on the cellulose acetate, of anthracene, said cellulose acetate containing from 42.5 to 44.0 per cent by Weight acetyl.

RALPH H. TALBOT.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A PHOTOGRAPHIC ELEMENT COMPRISING AT LEAST ONE PHOTOGRAPHIC SILVER HALIDE EMULSION LAYER AND A COLORLESS CELLULOSE ACETATE LAYER CONTAINING FROM 0.01 TO 0.20 PER CENT BY WEIGHT, BASED ON THE CELLULOSE ACETATE, OF ANTHRACENE, SAID CELLULOSE ACETATE CONTAINING FROM 42.5 TO 44.0 PER CENT BY WEIGHT ACETYL. 